The sweet pea (Lathyrus odoratus L.) was discovered in Sicily in 1695 (Rice, 2002). Many cultivars have been bred in England and the United States since its introduction in England.
Sweet pea cultivation is popular not only in the United Kingdom and the United States, but also in Europe, Russia, Egypt, New Zealand, Australia, and Japan (Hambidge, 1996; Inoue, 1981, 2007; Rice, 2002). There are some reports of commercial sweet pea cut flower production (Hammett, 2006; Inoue, 1981; Parsons, 2004). However, the quantity of cut flower production worldwide is unknown because there are no statistics available. The majority of sweet pea seed is produced by California in the United States and by New Zealand (Hambidge, 1996; Inoue, 1981, 2007; Rice, 2002).
The date when the sweet pea was introduced in Japan is unclear, but commercial culture started in 1929 (Inoue, 2007). In 2004, the value of sweet pea cut flower production in Japan was ≈$27 million U.S. (JPN ¥ 2.9 billion) (Japan Flower Promotion Center, 2004). The sweet pea is a very popular cut flower in Japan and is marketed from November to April. It is a major cut flower crop and is grown to meet the demand.
The sweet pea has three flowering types: winter, spring, and summer (Inoue, 2002). In Japan, most growers grow cultivars of the winter and spring flowering types because cultivars of both types require cold storage of germinated seed for vernalization to induce flowering from November. Cultivars of the summer flowering type, however, also need long-day treatment to induce flowering.
Most Japanese growers maintain their own seed by heritage seed production because imported commercial seed does not have stabilized flowering types or flower colors when grown in Japan. Most cultivars grown in Japan have been selected and established from imported market seed by Japanese growers.
The Miyazaki Agricultural Research Institute is situated in Miyazaki prefecture, the biggest sweet pea cut flower production region in Japan. To promote sweet pea production in Miyazaki prefecture, we are trying to breed new cultivars that have desirable qualities and yield. ‘Mimi’ sweet pea, shown in Figure 1, a new cultivar with desirable qualities and high yield, is reported here.
Beal, A.C. 1914 Sweet-pea studies, IV. Classification of garden varieties of the sweet pea Bul. Cornell Univ. Coll. Agr. 342 213 360
Inoue, T. 2002 Effects of seed vernalization and photoperiod on flower bud initiation of summer, spring, and winter flowering types of sweet pea (Lathyrus odoratus L.) J. Jpn. Soc. Hort. Sci. 71 127 132 [in Japanese literature with English abstract].